I said in the very first post in this "long" thread
if the PSU is dirty or isn't getting enough air flow it i will stop,
You have even suspected that the back of the PSU was getting hot, looks like your initial troubleshooting went wrong and led you (and us for that matter) into thinking it was something else.
And FYI, this isn't an S19 only a problem, it's common with the 17 series as well, the S17 Pro is kind of an expectation due to its high efficiency and relatively low overall power consumtion, of course, weaker fans on the S19 PSU could make this problem even worse, but bad PSU airflow is a very common problem.
Thanks for reporting back (most people don't), it was quite a ride, but we all learned some stuff along the way. Mine on.
Yeah. The reason I did not suspect it to be the psu is because the chips on the boards are below 50 and the psu is cool to the touch. Also its 40f degrees inside the container. So I assumed it cant be the psu. (The PSU's are brand new and have zero dust). Also I have an even worse heat situation with the s17+ and none of them have problems. These S19 Pro have very sensitive PSU's when compared to the S17+.